Astronaut to spacewalk to fix shuttle

Posted: Tuesday, August 02, 2005

By Marcia DunnAssociated Press

SPACE CENTER, Houston - NASA announced Monday that an astronaut will perform a spacewalk to fix two worrisome pieces of filler material protruding from Discovery's belly - a high-stakes operation to repair a problem that could threaten the shuttle during re-entry.

Wayne Hale, the deputy shuttle program manager, told a news conference that engineers simply did not know enough about the problem to leave it unattended, so they decided to conduct the spacewalk Wednesday to "set our minds at rest."

"At the end of the day, the bottom line is there is large uncertainty because nobody has a very good handle on the aerodynamics at those altitudes and at those speeds," Hale said. "Given that large degree of uncertainty, life could be normal during entry or some bad things could happen."

NASA managers have spent the last few days trying to decide whether the cloth strips could cause overheating during re-entry and lead to another Columbia-type disaster.

The ceramic-fiber cloth that is used to fill the gaps between Discovery's thermal tiles is sticking out an inch or less in two spots, and some engineers worry the material might disturb the air flow enough during re-entry to cause a dangerous heat buildup beneath the spaceship.

Astronauts have never ventured under an orbiting shuttle before, and have never attempted to fix their ship's thermal shielding in flight.

The plan called for the operation to be performed by Stephen Robinson on the end of the space station's 58-foot robot arm, which would bend and wrap around the side of Discovery to enable him to reach all the way underneath.

Robinson will first try to tug the dangling strips out with his gloved fingers. If that does not work, he will use a hacksaw to cut them off while holding the material taut with forceps.